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• \nDimension: 2\" diameter
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• \nThickness: 350 +/- 25 um\n
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• \nUsable area: >70%
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• \nOrientation: C-plane (0001) off angle toward M-axis <1-100> 0.35 deg +/- 0.15 deg
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• \nTotal Thickness Variation: <15 um
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• \nBow: <20 um
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• \nResistivity (300K): >10⁶  Ohm-cm\n
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• \nFe-doping concentration: ~ 3 × 10¹⁸ cm⁻³\n
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• \nDislocation Density: <3 x 10⁶ cm^-2
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• \nPolishing: Front surface: Ra <0.5 nm, epi-ready polished. back surface fine ground.\n
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• \nPackage: packaged in a class 100 clean room environment, in single wafer container, under nitrogen atmosphere.
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1. Study of GaN light-emitting diodes fabricated by laser lift-off technique

The fabrication process and performance characteristics of the laser lift-off (LLO) GaN light-emitting diodes (LEDs) were investigated. The LLO-GaN LEDs were fabricated by lifting off the Gallium Nitride LED wafer structure grown on the original sapphire substrate by a KrF excimer laser at 248 nm wavelength with the laser fluence of 0.6 J/cm2 and transferring it onto a Cu substrate. The LLO-GaN LEDs on Cu show a nearly four-fold increase in the light output power over the regular LLO-LEDs on the sapphire substrate. High operation current up to 400 mA for the LLO-LEDs on Cu was also demonstrated. Based on the emission wavelength shift with the operating current data, the LLO-LEDs on Cu show an estimated improvement of heat dissipation capacities by nearly four times over the light-emitting devices on sapphire substrate. The LLO process should be applicable to other GaN-based LEDs in particular for those high light output power and high operation current devices.